Originally Posted by wphamilton

500 full charges is the (max) full life of the battery. But only charge it to 60-65% instead of 100%, and 4,000 charges is the life of the battery.

I think that you're confirming that we care mostly about the battery capacity and not the battery life for most items, because we only even consider the full charge. Objectively, I'm that way myself. Give up a day or half a day of run-time on my phone's charge, just to make the battery last longer? Would I rather have it last for 2 or 3 years but only ever use 65% of the battery? No way, I'll just buy another battery in a year. But I did just now download a battery app to cut of charging at around 80% or 90% - all I really care about is one day of use.

On an e-bike battery pack costing $600 or more to replace, that would be another story. I'd want to get the 4,000 charge cycles out of it instead of 500, if I could. So if this is all correct, buying twice the battery you need and charging it only to 60% is far and away the best strategy cost-wise.